Product name: 2.1 channel Bluetooth audio amplifier moduleMaterial: PCB+metalProduct : -LT21Bluetooth version: 5.1Audio channel: 2.1 channelColor: BlackInput mode: Bluetooth+AUX+USB+USB sound card supply: above DC9-24V/3AAudio output: left channel 15W+right channel 15W+subwoofer 30WAdaptive horn: 10W-50W/4 - 8 Output : 15W x 2 (left and right channels)+30W (subwoofer)Volume adjustment: high-end encoder knob adjustment, smooth feelProtection mechanism: overheating, overcurrent, short circuit, anti-static protectionSpecial function: support Audio APP controlProduct size: 75 x 60 x 22 mmProduct weight: net weight 66gNote: It is recommended to equip an 8 horn with supply of 9-24V DC. Overvoltage is not allowed. If the 4 horn is driven, the supply cannot exceed 12V.Package Contents:1 x -LT21 amplifier board1 x DC adapter1 x screwdriverOnly the above package content, other products are not included.Note: Light reflection and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.